我从 API 的 JSON 格式获取文本，现在我想在我的 android 应用程序中从相同的 API 添加图像

Question

我是 android 的新手，发现很难从 API 的 JSON 格式更新实时文本和图像。我已成功将文本添加到我的列表视图中。现在我想在它旁边添加图像。提前致谢。

MainActivity.java 文件

package com.example.android.samplelayout;

import android.media.Image;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.ImageView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter; 
import android.widget.Toast;
import android.net.Uri;
import android.graphics.drawable.Drawable;

import org.json.JSONArray;
import org.json.JSONException;
 import org.json.JSONObject;

import java.net.URI;
import java.util.ArrayList;
import java.util.HashMap;

public class MainActivity extends AppCompatActivity {

private String TAG = MainActivity.class.getSimpleName();
private ListView lv;

ArrayList<HashMap<String, String>> contactList;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    contactList = new ArrayList<>();
    lv = (ListView) findViewById(R.id.list);

    new GetContacts().execute();
}

private class GetContacts extends AsyncTask<Void, Void, Void> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        Toast.makeText(MainActivity.this,"Json Data is downloading",Toast.LENGTH_LONG).show();

    }

    @Override
    protected Void doInBackground(Void... arg0) {
        HttpHandler sh = new HttpHandler();
        // Making a request to url and getting response
        String url = "http://webhose.io/search?token=9c55cbb1-2f1c-4700-9c1e-67e685152506&format=json&q=Indian%20Startup";
        String jsonStr = sh.makeServiceCall(url);

        Log.e(TAG, "Response from url: " + jsonStr);
        if (jsonStr != null) {
            try {
                JSONObject jsonObj = new JSONObject(jsonStr);
                // Getting JSON Array node
                //JSONObject responseObject = jsonObj.getJSONObject("response");
                JSONArray responseArray = jsonObj.getJSONArray("posts");
                // looping through All Contacts
                for (int i = 0; i < responseArray.length(); i++) {


                    JSONObject firstObject = responseArray.getJSONObject(i);
                    //JSONObject titleObject = firstObject.getJSONObject("title");
                    // Extract out the title, time, and tsunami values

                    //String image = firstObject.getString("main_image");
                    String title = firstObject.getString("title");

                    // tmp hash map for single contact
                    HashMap<String , String> contact = new HashMap<>();

                    // adding each child node to HashMap key => value
                    //contact.put("pic", image);
                    contact.put("name", title);

                    // adding contact to contact list
                    contactList.add(contact);
                }
            } catch (final JSONException e) {
                Log.e(TAG, "Json parsing error: " + e.getMessage());
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(getApplicationContext(),
                                "Json parsing error: " + e.getMessage(),
                                Toast.LENGTH_LONG).show();
                    }
                });

            }

        } else {
            Log.e(TAG, "Couldn't get json from server.");
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    Toast.makeText(getApplicationContext(),
                            "Couldn't get json from server. Check LogCat for possible errors!",
                            Toast.LENGTH_LONG).show();
                }
            });
        }

        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        ListAdapter adapter = new SimpleAdapter(MainActivity.this, contactList,R.layout.list_item, new String[]{"name"}, new int[]{ R.id.name});
        lv.setAdapter(adapter);
    }
}



}

HttpHandler.java 文件

package com.example.android.samplelayout;

import android.util.Log;

import java.io.BufferedInputStream; 
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;

public class HttpHandler {

private static final String TAG = HttpHandler.class.getSimpleName();

public HttpHandler() {
}

public String makeServiceCall(String reqUrl) {
    String response = null;
    try {
        URL url = new URL(reqUrl);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        // read the response
        InputStream in = new BufferedInputStream(conn.getInputStream());
        response = convertStreamToString(in);
    } catch (MalformedURLException e) {
        Log.e(TAG, "MalformedURLException: " + e.getMessage());
    } catch (ProtocolException e) {
        Log.e(TAG, "ProtocolException: " + e.getMessage());
    } catch (IOException e) {
        Log.e(TAG, "IOException: " + e.getMessage());
    } catch (Exception e) {
        Log.e(TAG, "Exception: " + e.getMessage());
    }
    return response;
}

private String convertStreamToString(InputStream is) {
    BufferedReader reader = new BufferedReader(new InputStreamReader(is));
    StringBuilder sb = new StringBuilder();

    String line;
    try {
        while ((line = reader.readLine()) != null) {
            sb.append(line).append('\n');
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    return sb.toString();
}
}

Answer 1

我建议使用仅使用您要使用的图像的 Url 自动将图像放入 ImageView 的库。 Picasso 将是一个很好的图书馆供您使用。您必须从 Json 对象中获取图像 URL 并使用 Picasso 的 load().into()

将其加载到 ImageView 中